Cheers for the headsup. I've been looking at stuff from M-Audio (among others) but whenever I find something that's listed as USB Audio Interface, it only seems to use the USB as the connection to the laptop - I need something that connects to the pc with USB, and also accepts input of MIDI controllers via USB (I've got a Novation X-Station keyboard which connects through USB - not sure if that makes it technically a MIDI keyboard or not...)

I'm very baffled. Does such a thing even exist? /considers contacting some friendly aliens.